Touch panels are now widely employed in for example a display of a portable computer, input means of a portable personal communication device, various household electrical appliances, public information systems, and office automation devices.
FIG. 1 of the attached drawings shows an exploded view of a conventional touch panel. The conventional touch panel, which is generally designated at 100 in FIG. 1, comprises a glass substrate 11 having a surface on which a transparent conductor layer 111, such as an ITO layer, is coated so that the glass substrate 11 and the transparent conductor layer 111 form an electrically conductive glass panel. The electrically conductive glass panel is covered with a film 12, which has a bottom surface coated with a transparent conductor layer 121 opposing the transparent conductor layer 111 of the glass substrate 11. A plurality of insulation spacer nodes 13 is arranged between the transparent conductor layer 111 of the glass substrate 11 and the transparent conductor layer 121 of the film 12 to separate the transparent conductor 111 from the transparent conductor layer 121. Often, a protection layer 14 is provided to cover a top face of the film 12.
The transparent conductor layer 111 of the glass substrate 11 and the transparent conductor layer 121 of the film 12 are respectively provided with signal contacts 112, 122 to which a signal transmission cable 15 is connected to send out signals generated due to depression or actuation of the touch panel 100.
In the manufacturing of the touch panel 100, a conventional manufacturing process comprises etch-resistant printing applied to a glass substrate, etching and film peeling, printing of insulation spacer nodes, printing of sliver lines, printing of insulation layer, and printing of frame to complete the manufacturing of an electrically conductive glass panel. The manufacturing of the conductor film is substantially similar. The electrically conductive glass panel and the conductor film so manufactured are then stacked together, and thereafter subjected to trimming and connection with a flat cable to complete the manufacturing of the touch panel.
After the touch panel has been so manufactured, a linearity testing is taken to inspect if the touch panel meets the required electrical performance and satisfies the desired quality. The linearity testing is a major testing for electrical characteristics.
In the conventional method for carrying linearity testing, as shown in FIG. 2, a practical touch/depression is carried out for the testing, wherein a pressurizing testing stylus 2 is positioned on the touch panel 100 to actually touch and depress the surface of the touch panel 100. As to the connection of signal, the signal transmission cable 15 is connected to a testing system 3 in which programs for reading and analyzing signals are pre-loaded so that the testing system 3 reads signals from the touch panel 100 through the signal transmission cable 15 and further analyzes the signals so read for displaying on a display 4 connected to the testing system 3. To carry out the testing, the pressurizing testing stylus 2 touches and depresses the touch panel 100 along a predetermined testing route L defined in directions of X-axis and Y-axis to apply pressure to, draw lines on, and make displacement on the touch panel 100, whereby due to the pressurization of the touch panel 100, the transparent conductor layer 111 of the glass substrate 11 and the transparent conductor layer 121 of the film 12 of the touch panel 100 are forced to get into contact with each other, inducing a signal of touch. The signal of touch is then transmitted through the signal transmission cable 15 to the testing system 3 and is subsequently read and analyzed by the testing system 3, and a testing route L′ corresponding to the signals read is displayed on the display 4 of the testing system 3. Based on the result displayed, a determination can be made if the touch panel is qualified for the linearity testing.
In such a conventional manner of testing, where a pressurizing testing stylus is used to carry out the testing of a touch panel, direct contact and pressurization are applied to the surface of the touch panel to carry out the testing so that the pressurizing testing stylus itself becomes a major factor of testing for the touch panel. For example, the contact pressurization applied by the pressurizing testing stylus and line-drawing and displacement of the pressurizing testing stylus must be controlled by a specific jig or controller. Poor design of the jig or controller and irregularity on a contact point of the pressurizing testing stylus or the surface of the touch panel all are potential causes for damage and/or scrape of the surface of the touch panel. Even a tiny scrape or damage may make the touch panel an unacceptable product by the consumers when the touch panel product is put into market. In addition, in case that tiny contamination particles attach on the surface of the touch panel at the time the testing is carried out, the pressurizing testing stylus, when displacing on the surface of the touch panel, may be stuck by the particles, may apply a pressure to the surface of the touch panel through the particles that exist between the pressurizing testing stylus and the surface of the touch panel, again causing undesired damage on the surface of the touch panel.
Further, in addition that the touch panel product has to meet the requirement of linearity testing, the touch panel is also tested to make sure that it has acceptable electrical characteristics. For example, the relationship between the contact pressure applied to the touch panel and the touch signal generated by the touch panel is considered a major indication for satisfaction of quality requirement of the touch panel. However, heretofore, inspection and testing of a touch panel product are only carried out for the linearity testing and no testing to the electrical performance has been done and suggested.
Thus, the present invention is aimed to overcome such a drawback occurring in the conventional testing of a touch panel that is carried by a pressurization testing stylus in order to ensure the quality of touch panels and to examine electrical performance of the touch panel products.